There's no cure for a bad smartphone battery outside of carrying extra packs or a charger with you.

However, if you use your Android carefully, the operating system lets you control your battery usage by paying attention to what applications are sucking the most power.

Based on that information, you can pinpoint where to cut off access so your phone won't be able to automatically run your battery down.

Here are some tips on what you can do to conserve as much battery power as possible, whether you're being frugal or need an emergency supply.

Note: We used a SamsungGalaxy S II for this story, but the tips will apply to most Android phones.

Under Settings, look for the About phone button to check out your phone's current status and battery use

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In general, the top two will always be Display and Android System since they are the core of what's running your device. Here, you can see the estimated time of battery life you have left.

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To reduce the battery suckage from your display, make sure you turn Brightness off whenever possible. Access this under Settings > Display or from one of your phone's shortcut screen.

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If you're not using your phone to access the Internet, also make sure Wi-Fi is turned off under Wireless and networks.

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You can also turn off your phone's data packet if you're that desperate for battery, though that means your smartphone will be as good as a dumb phone at that point. At least it'll make calls!

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Back under Wireless and networking, visit the Bluetooth setting and turn that off if you had previously left it on.

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At the shortcut screen, you'll notice a button with how many applications you're currently running at the top right corner.

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To access this Task Manager, you can hold the home button on your phone to bring up a shortcut.

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Kill all the applications you're running to conserve juice. Pesky apps like Web and Messaging will like to stay running in the background unless you manually kill them off.

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Under Settings > Location and security, you should also turn off wireless networks and GPS satellites. The satellites constantly run in the background so your maps application can always pinpoint your geo-location.

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You can easily turn all of this off in one fell swoop on the shortcut screen by tapping anything that's green. Furthermore, clicking the settings button takes you a list of all the optional features you can disable to save battery.

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When your battery is critical, use the Power saving mode. You can set this to turn on automatically when your battery drops below a certain percentage. While you're here, you have the option of turning everything off, or just the one you really need on.